Besides standard detergents, there is an increasing availability of combination products, called “multiple-in-1” products, for use in dishwashers. 2-in-1 detergents contain a rinse agent in addition to the detergent agent, while 3-in-1 detergents additionally contain a water-softening agent. There are also 4-in-1 and 5-in1 detergents, which contain further components. According to manufacturer specifications, there is no need to use rinse aid or water softener salt when using such products, provided the tap water hardness does not exceed 21° dH. In many cases, this leads to poorer washing and/or drying results. In particular, the rinse performance of combination products frequently does not reach the level of a separately dispensed liquid rinse aid. Therefore, there is a desire to improve washing results by adapting the wash cycles, such as described, for example, in DE 10 2004 043 657 A1 or EP 1 362 547 A2. In German Patent documents DE 100 49 489 A1, DE 102 20 839 A1 and DE 102 30 567 A1, other forms of cycle adaptation are described according to which rinse aid and salt indicators are disabled when not needed.
Basically, when using combination products, the dishwasher must use different cycle sequences than when using standard detergents in order to obtain satisfactory washing and drying results. When using combination products, such differences include the suppression or reduction of the rinse agent supply and regeneration cycles, longer cycle times (especially of the drying step), higher liquid temperatures during the final rinse step, and reduced water changes (suppression of the second intermediate rinse step.
In the dishwashers described in DE 100 49 489 A1, DE 102 20 839 A1 and DE 102 30 567 A1, adapted wash cycles are selected via additional control elements. To this end, the dishwasher of DE 102 20 839 A1 is provided with additional, momentary buttons which can be pressed to select all cycles from the 2-in-1 group or 3-in-1 group that are to be used in the future. This variant is indeed simple in construction, but has the disadvantage that when users switch from combination products to standard detergents, they often forget to release buttons they have pressed before.
Therefore, there is a desire to allow wash cycles to be automatically adapted when combination products are used. European Patent Document EP 1 362 547 A2 describes a way of detecting the detergent type using sensor means. The sensors used are chemical, optical, acoustic, thermal or pneumatic sensors, which analyze the effect of the detergent on the wash liquid and which are intended to detect therefrom the type of product used. This has proved not to be practical because the differences in the degree of soiling of the dishes corrupt the measurement results of the sensors. Moreover, such sensors are expensive and prone to failure, and are therefore not suitable for use in consumer products.
Document WO 2004/017807 A1 describes a method of the aforementioned type in which a standard wash cycle is set as a default cycle and in which, when there is no water softener salt and/or rinse aid available, the dishwasher infers that a combination product is used, and adapts the sequence of the wash cycle accordingly. However, the absence of the aforementioned agents is not an unequivocal sign that combination products are used. The user may also have forgotten to replenish said agents. DE 100 49 489 A1 describes that the rinse aid indicator may be disabled after switching to an adapted cycle. In that case, absence of this agent is not indicated to the user, and wash cycles are performed without the addition of rinse aid, even when using standard detergents.